package com.leetcode;

public class Leetcode072 {
    public int minDistance(String word1, String word2) {
        int m = word1.length();
        int n = word2.length();

        int[][] dp = new int[m + 1][n + 1];

        //word1第i个字符去匹配 word2的第0个字符，相当于全部删掉
        //因此 dp[i][0] = i
        for (int i = 0; i < m + 1; i++) {
            dp[i][0] = i;
        }
        //word1第0个字符去匹配 word2的第j个字符，相当于全部插入
        //因此 dp[0][j] = j
        for (int j = 0; j < n + 1; j++) {
            dp[0][j] = j;
        }

        for (int i = 1; i < m + 1; i++) {
            for (int j = 1; j < n + 1; j++) {
                if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = Math.min(dp[i - 1][j - 1],
                            Math.min(dp[i - 1][j], dp[i][j - 1])) + 1;
                }
            }
        }
        return dp[m][n];
    }

    public static void main(String[] args) {
        String word1 = "horse";
        String word2 = "ros";
        Leetcode072 leetcode = new Leetcode072();
        System.out.println(leetcode.minDistance(word1, word2));
    }
}
